Dr. Munajid Al-Tamimi (Diploma in Obstetrics and Reproductive Diseases)
13/9/2026
Determining the animal source of meat is a crucial aspect of food control, playing a vital role in detecting commercial fraud, protecting consumers, and verifying the accuracy of product labeling. This article briefly reviews the methods used to distinguish between beef, pork, and donkey meat, ranging from visual and sensory inspection to DNA-based molecular tests. While characteristics such as color, texture, fat distribution, and muscle fibers serve as preliminary indicators, they are insufficient to conclusively identify the animal species; definitive diagnosis requires appropriate laboratory methods, most notably PCR.
Introduction
Meat adulteration—specifically the substitution of one animal species for another—is an issue that impacts food safety and consumer rights, in addition to having economic and religious implications. Identifying the animal source becomes increasingly difficult with minced, processed, and cooked meats, as these products lose many of their distinctive anatomical and visual characteristics. Consequently, modern food control protocols rely on a combination of preliminary inspection and laboratory testing, avoiding definitive conclusions based solely on external appearance.
Visual and Sensory Inspection
Preliminary inspection involves observing muscle color, fat distribution, the nature of muscle fibers, texture, and odor. While differences between meat types may be apparent, they are not consistent enough to allow for definitive species identification. Color, for instance, is influenced by myoglobin content, the animal’s age, muscle type, the extent of oxygen exposure, and storage duration and conditions. Similarly, fat content, color, and distribution vary based on the animal’s breed, age, diet, and body condition. Therefore, asserting that a specific color or texture necessarily indicates the meat is from cattle, pigs, or donkeys is scientifically inaccurate. Such characteristics serve only to raise suspicion and guide further examination, rather than conclusively identifying the species.
Laboratory Analysis
When the substitution of one meat type for another is suspected, laboratory tests offer greater reliability. Techniques based on proteins and immunoassays, as well as DNA-based molecular methods, are employed for this purpose. DNA analysis methods are distinguished by their ability to identify animal species with high specificity; furthermore, DNA is relatively more stable than certain proteins in processed products.
PCR Technology
Polymerase Chain Reaction (PCR) technology is a vital tool for verifying the animal source of meat by amplifying specific DNA segments unique to the target species. Species-specific PCR can be used to detect a particular species, whereas multiplex PCR allows for the simultaneous detection of multiple species in a single test. Real-time PCR (qPCR) is also utilized for the sensitive and specific detection of animal DNA. Other methods—such as PCR-RFLP, DNA sequencing, and DNA barcoding—are also available; the appropriate technique is selected based on the sample type, the objective of the analysis, and available laboratory capabilities. The Importance of Identifying Meat Types
Verifying the animal source of meat helps combat food fraud, protects consumers, enhances health and veterinary oversight, and ensures the accuracy of food labeling; it is also crucial for products subject to specific religious or legal restrictions. For consumers, the best preventive measure is to purchase meat from trusted sources and shops subject to health and veterinary inspections, while avoiding products of unknown origin. One should not rely solely on color, odor, or the appearance of fat to determine the animal species, particularly with ground or processed meats.
Conclusion
Visual and sensory inspections can provide preliminary indicators that alert inspectors or veterinarians to potential discrepancies in the nature of the meat, but they do not constitute definitive proof of the animal species. When reliable identification of the animal source is required, appropriate laboratory tests should be employed. Molecular techniques—specifically PCR and Real-Time PCR—are among the most important tools for verifying meat authenticity and detecting substitution or fraud.
Public Awareness Message
Meat type cannot be conclusively determined by color or appearance alone. Purchase meat from trusted sources; if there is any suspicion, laboratory testing is the most accurate method for verifying the animal species.
References
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Why can’t we get rid of these cheeses?
Dr. Milad Ibrahim Oraibi
31/8/2026
Initially, when the virus enters the poultry house and is inhaled through the nose, it attacks ciliated epithelial cells, leading to their death and damage. This results in the infiltration of many heterophile cells into the trachea due to severe inflammation. These cells lack the enzyme myeloperoxidase, which breaks down proteins as neutrophils do in mammals. Consequently, the dead cells do not decompose into mucus but rather clump together into a thick, coagulated tissue. Fibrin, along with other inflammatory fluids rich in fibrinogens from damaged blood vessels, transforms into a network of fibrin fibers composed of dead cells, heterophiles, and any secondary viruses and bacteria present in the tracheal lumen. This material then gradually dries and hardens within the trachea due to the inhaled and exhaled air. Then it turns into a yellow substance with a gelatinous consistency, and then into a strong, curd-like substance that resembles cheese in appearance.
The important thing in the process is that the heterophile cells in poultry lack strong enzymes for breakdown such as (MPO and Elastase). These enzymes lead to the breakdown of dead cells and their breakdown with damaged tissues into a final product called (liquid pus), as in mammals. The absence of this mechanism will lead to the retention of dead cells with heterophile cells, which, if they turn into a liquid form, will adhere strongly to each other, which will be the caseous mass (liquefactive necrosis failure).
There is an important point: when the virus enters the epithelial cells and the endothelial cells, a strong immune response will occur, and pro-inflammatory cytokines will be secreted, namely IL, IB, IL6, and TNF-a. Because of this process, vascular permeability will increase, and this in turn will allow large quantities of proteins and high molecular weight plasma to pass through, the most important of which is fibrinogen.
When fibrinogen comes into contact with factors such as tissue factor released from dead and damaged epithelial cells, coagulation, clotting, or hardening will occur, and fibrin will be converted into insoluble fibrin meshwork, which will trap the damaged and destroyed cells inside.
Then this network turns into (coagulation and caseous necrosis) where there is a lack of blood supply to the damaged and destroyed area caused by the blockage of microscopic capillaries by (microthrombosis) and eventually (coagulative necrosis) will occur.
After the rapid passage of air through inhalation and exhalation, and due to accelerated breathing (hyperventilating) resulting from a lack of oxygen in the body, drying of the formed materials will occur and form (fibrinonecrotic mass), then it gradually turns from a soft mucous consistency to a solid, cohesive consistency resembling cheese called (caseous plug) and takes the shape of a tracheal cast.
The cause of chicken death is:
１- Mechanics due to respiratory tract obstruction
２- Lack of oxygen and the heart’s inability to work
３- Blood poisoning caused by gas retention and bacterial contamination
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